The number of situations of users carrying about mobile phones, mobile information terminals, portable devices reproducing music or video, or game machines, to say nothing of notebook personal computers, is increasing. These electronic devices are required to be of high reliability under a variety of adverse using environments, including a drop impact load, car vibrations and so forth. Hence, an increasing demand is placed on a technique of high strength component packaging. On the other hand, since the number of components packaged increases with function augmentation, there is a strong demand for development of high density thin thickness packaging techniques. Since the high density, thin thickness and the high strength are in contradiction to one another, a wide variety of reports have been made in connection with techniques targeted at realization of high density and thin thickness. Under these situations, LGA (Land Grid Array) type packages are coming into widespread use to reduce the thickness of the packaging structures of the semiconductor packages.
There is simultaneously raised a demand for narrow pitch, such that, in the field of secondary packaging, the demand for low height ascribable to use of the LGA and the demand for narrow pitch need to be satisfied together. On the other hand, in a new type package, such as SiP (System In Package) or PoP (Package on Package), the package tends to be increased in size.
To take the above into account and to maintain the same reliability as before, it is a frequent occurrence that reinforcement by an underfill resin becomes necessary. As techniques to cope with the demand for a larger area and a narrow gap, the following techniques have so far been proposed. In Patent Document 1, for example, there is proposed a technique of previously supplying a resin to a packaging area of a semiconductor package in place of applying resin from a lateral side to permit its permeation. In Patent Document 2, there is proposed a technique of using surface-modified spherical silica as a filler material used for reinforcement to improve its fluidity.    [Patent Document 1] JP Patent Kokai Publication No. JP-P2004-312051A    [Patent Document 2] JP Patent Kokai Publication No. JP-P2004-292250A    [Non-Patent Document 1] ‘Optical Catalyst’, edited by Japan Society of Chemistry, edited and supervised by Akira Fujishima, Maruzen Company, September 2005